| To change the default values for m and v, press Reset before
entering your values for mass and velocity. The velocities |
| can be either positive or negative. The default x-positions are -1.00
m for the red ball and +1.00 m for the blue ball. |
| To change the default x-positions, press Reset before entering
the values. For instructional purposes, you can verify the |
| velocities or determine that Δp = 0 or ΔKE ≠ 0 for the
collision. |
| |
| Inelastic collisions are those collisions that involve a change in kinetic
energy. Generally, the kinetic energy decreases |
| because some of the kinetic energy is converted to sound, light, heat,
and/or a deformation of the colliding objects. It is |
| important to note that energy is not lost but
rather transformed. This animation deals with the special case which is
a |
| completely inelastic collision where the objects stick together after
the collision. Examples of such collisions are |
| railroad cars and football players (i.e. a running back and a linebacker)
colliding, sticking together, and moving with the |
| same velocity. |
| |
| For the system described above, the kinetic energy is not conserved.
Mathematically this is expressed as: |
| |
|
ΔKE ≠ 0 |
|
KEi ≠ KEf |
|
1/2m1v12 + 1/2m2v22
≠ 1/2m1v1'2 + 1/2m2v2'2
|
| |
| It is extremely important to keep in mind that in both elastic and inelastic
collisions, momentum is conserved. |
| Mathematically this is expressed as: |
| |
|
Δp = 0 |
|
pi = pf |
|
m1v1 + m2v2 = m1v1'
+ m2v2' |
| |
| Also, check out One
Dimensional Elastic Collisions. |
| |
| 1) A 2.0 kg block moving 3.5 m/s to the right collides with a 6.0 kg
block moving 2.0 m/s to the left. Ignoring |
| friction, determine the: |
| (a) final velocity if the two blocks stick together. |
| (b) amount of heat produced. |
| (c) final velocity if the collision was completely
elastic. |
| |
| 2) A 10.0 g bullet is moving with a horizontal velocity of 40.0 m/s
into a 8.0 kg block of wood which is at rest. If the |
| bullet becomes embedded in the wood what is
the final velocity of the wooden block? |
